From: Gao feng <gaofeng@cn.fujitsu.com>
To: netfilter-devel@vger.kernel.org
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Subject: [PATCH 1/2] xt_TCPMSS：Get reserve mtu only when specifing option clamp-mss-to-pmtu
Date: Thu, 26 Sep 2013 15:00:30 +0800 [thread overview]
Message-ID: <1380178831-20360-1-git-send-email-gaofeng@cn.fujitsu.com> (raw)
Don't get reserve mtu when user sepcifies the mss through
set-mss.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
---
net/netfilter/xt_TCPMSS.c | 70 ++++++++++++++++++++++++-----------------------
1 file changed, 36 insertions(+), 34 deletions(-)
diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c
index cd24290..62776de 100644
--- a/net/netfilter/xt_TCPMSS.c
+++ b/net/netfilter/xt_TCPMSS.c
@@ -43,10 +43,41 @@ optlen(const u_int8_t *opt, unsigned int offset)
return opt[offset+1];
}
+static u_int32_t tcpmss_reverse_mtu(const struct sk_buff *skb,
+ unsigned int family)
+{
+ struct flowi fl;
+ const struct nf_afinfo *ai;
+ struct rtable *rt = NULL;
+ u_int32_t mtu = ~0U;
+
+ if (family == PF_INET) {
+ struct flowi4 *fl4 = &fl.u.ip4;
+ memset(fl4, 0, sizeof(*fl4));
+ fl4->daddr = ip_hdr(skb)->saddr;
+ } else {
+ struct flowi6 *fl6 = &fl.u.ip6;
+
+ memset(fl6, 0, sizeof(*fl6));
+ fl6->daddr = ipv6_hdr(skb)->saddr;
+ }
+ rcu_read_lock();
+ ai = nf_get_afinfo(family);
+ if (ai != NULL)
+ ai->route(&init_net, (struct dst_entry **)&rt, &fl, false);
+ rcu_read_unlock();
+
+ if (rt != NULL) {
+ mtu = dst_mtu(&rt->dst);
+ dst_release(&rt->dst);
+ }
+ return mtu;
+}
+
static int
tcpmss_mangle_packet(struct sk_buff *skb,
const struct xt_action_param *par,
- unsigned int in_mtu,
+ unsigned int family,
unsigned int tcphoff,
unsigned int minlen)
{
@@ -76,6 +107,8 @@ tcpmss_mangle_packet(struct sk_buff *skb,
return -1;
if (info->mss == XT_TCPMSS_CLAMP_PMTU) {
+ unsigned int in_mtu = tcpmss_reverse_mtu(skb, family);
+
if (dst_mtu(skb_dst(skb)) <= minlen) {
net_err_ratelimited("unknown or invalid path-MTU (%u)\n",
dst_mtu(skb_dst(skb)));
@@ -165,37 +198,6 @@ tcpmss_mangle_packet(struct sk_buff *skb,
return TCPOLEN_MSS;
}
-static u_int32_t tcpmss_reverse_mtu(const struct sk_buff *skb,
- unsigned int family)
-{
- struct flowi fl;
- const struct nf_afinfo *ai;
- struct rtable *rt = NULL;
- u_int32_t mtu = ~0U;
-
- if (family == PF_INET) {
- struct flowi4 *fl4 = &fl.u.ip4;
- memset(fl4, 0, sizeof(*fl4));
- fl4->daddr = ip_hdr(skb)->saddr;
- } else {
- struct flowi6 *fl6 = &fl.u.ip6;
-
- memset(fl6, 0, sizeof(*fl6));
- fl6->daddr = ipv6_hdr(skb)->saddr;
- }
- rcu_read_lock();
- ai = nf_get_afinfo(family);
- if (ai != NULL)
- ai->route(&init_net, (struct dst_entry **)&rt, &fl, false);
- rcu_read_unlock();
-
- if (rt != NULL) {
- mtu = dst_mtu(&rt->dst);
- dst_release(&rt->dst);
- }
- return mtu;
-}
-
static unsigned int
tcpmss_tg4(struct sk_buff *skb, const struct xt_action_param *par)
{
@@ -204,7 +206,7 @@ tcpmss_tg4(struct sk_buff *skb, const struct xt_action_param *par)
int ret;
ret = tcpmss_mangle_packet(skb, par,
- tcpmss_reverse_mtu(skb, PF_INET),
+ PF_INET,
iph->ihl * 4,
sizeof(*iph) + sizeof(struct tcphdr));
if (ret < 0)
@@ -233,7 +235,7 @@ tcpmss_tg6(struct sk_buff *skb, const struct xt_action_param *par)
if (tcphoff < 0)
return NF_DROP;
ret = tcpmss_mangle_packet(skb, par,
- tcpmss_reverse_mtu(skb, PF_INET6),
+ PF_INET6,
tcphoff,
sizeof(*ipv6h) + sizeof(struct tcphdr));
if (ret < 0)
--
1.8.3.1
next reply other threads:[~2013-09-26 6:59 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-26 7:00 Gao feng [this message]
2013-09-26 7:00 ` [PATCH 2/2] xt_TCPMSS: lookup route in proper net namesapce Gao feng
2013-09-27 14:20 ` Pablo Neira Ayuso
2013-09-27 14:20 ` [PATCH 1/2] xt_TCPMSS：Get reserve mtu only when specifing option clamp-mss-to-pmtu Pablo Neira Ayuso
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1380178831-20360-1-git-send-email-gaofeng@cn.fujitsu.com \
--to=gaofeng@cn.fujitsu.com \
--cc=netfilter-devel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).